Wheeled vehicles such as automobiles, trucks, motorcycles, trains, bicycles and the like have a considerable amount of kinetic energy when the vehicle is in motion. For example, the mass of the vehicle may generate a considerable amount of mechanical kinetic energy as the vehicle is propelled forward with an engine, electric motor or even human power. However, during braking, the excess kinetic energy of the vehicle is primarily dissipated as heat emitted from the braking system. Because the kinetic energy of the vehicle is dissipated instead of being recaptured and stored, the overall energy efficiency of the vehicle is low.
Various systems have been developed to recapture the kinetic energy of a vehicle as the vehicle decelerates. For example, some gas/electric hybrid automobiles incorporate electrical regenerative braking systems which capture the kinetic energy of the automobile (e.g., the rotation of the wheels) during deceleration and convert the kinetic energy to electrical energy which is stored in a battery as electrical potential energy. While regenerative braking systems may improve the overall energy efficiency of the vehicle by capturing and converting some of the vehicle's mechanical kinetic energy to electrical potential energy, the process of converting the mechanical kinetic energy to electrical potential energy is relatively inefficient.
Accordingly, a need exists for alternative systems for recovering and storing the kinetic energy of a vehicle as mechanical potential energy and returning the mechanical potential energy to the drive train of the vehicle to assist in vehicle propulsion.